"If the Bill (Coal Mines) get passed (in Rajya Sabha) then there would be auction of 15-20 coal blocks. It (the auction) will start in April-end or the first week of May," Coal Secretary Anil Swarup said in an interview.

"We have identified about 15-20 coal blocks which can be put on auction. But we have to have Authority...only if we have a Bill or an Ordinance, without that we cannot have auction," Swarup said.

He said even in case the Bill does not get passed in Upper House, the ongoing auction process will not get impacted though the future auctions will be held back.

The Coal Ordinance which was re-promulgated in December would lapse on April 5.

"Whatever action has already been taken is deemed to be valid, so we would have completed all our actions before April 5. As far as ongoing auction process is concerned nothing will get impacted. But future auctions will get held back in case the Bill does not get passed," he said.

The Bill that seeks to replace the Ordinance was passed by the Lok Sabha but had to be referred to the Rajya Sabha Select Committee.

A parliamentary panel had yesterday recommended "no modification" in the existing legislation for auction of coal mines though its report contained dissident notes from five members including three from Congress on not protecting tribal rights and other issues.

"The Committee recommends enactment of the legislation without any modification," the 19-member Select Committee to examine the Coal Mines (Special Provision) Bill, 2015, headed by Anil Madhav Dave (BJP), said in its report tabled in Parliament.

The panel recommended passage of the Bill without any change.

Till date, a total of 33 coal blocks have been auctioned in two tranches. While in the first lot, 19 coal mines were auctioned, in the second as many as 14 coal blocks went under the hammer.